The present disclosure relates generally to multilateral wellbores and, more particularly, to an expandable bullnose assembly that works with a wellbore deflector to allow entry into more than one lateral wellbore of a multilateral wellbore.
Hydrocarbons can be produced through relatively complex wellbores traversing a subterranean formation. Some wellbores include one or more lateral wellbores that extend at an angle from a parent or main wellbore. Such wellbores are commonly called multilateral wellbores. Various devices and downhole tools can be installed in a multilateral wellbore in order to direct assemblies toward a particular lateral wellbore. A deflector, for example, is a device that can be positioned in the main wellbore at a junction and configured to direct a bullnose assembly conveyed downhole toward a lateral wellbore. Depending on various parameters of the bullnose assembly, some deflectors also allow the bullnose assembly to remain within the main wellbore and otherwise bypass the junction without being directed into the lateral wellbore.
Accurately directing the bullnose assembly into the main wellbore or the lateral wellbore can often be a difficult undertaking. For instance, accurate selection between wellbores commonly requires that both the deflector and the bullnose assembly be correctly oriented within the well and otherwise requires assistance from known gravitational forces. Moreover, conventional bullnose assemblies are typically only able to enter a lateral wellbore at a junction where the design parameters of the deflector correspond to the design parameters of the bullnose assembly. In order to enter another lateral wellbore at a junction having a differently designed deflector, the bullnose assembly must be returned to the surface and replaced with a bullnose assembly exhibiting design parameters corresponding to the differently designed deflector. This process can be time consuming and costly.